FR2705727A1 - Device for damping vibrations in vehicle exhaust pipes. - Google Patents

Abstract

The invention proposes a device for damping vibrations, in vehicle exhaust pipes, in particular, which involves less material expenditure than those of the devices known until now, is simpler to manufacture, and in particular allows a superior automation and rationalization. A device according to the invention has, in a manner known per se, elastic cushions (3) of press-formed wire, arranged in a housing (2), and is characterized in that wall sections of the front side casing (8, 9; 17, 18), external and juxtaposed, as stops of the elastic cushions, can move relative to each other.

Description

Device for damping vibrations in pipes

vehicle exhaust.

  The present invention relates to a vibration damping device, in vehicle exhaust pipes in particular, with an elastic cushion, at least, made of wire

  metallic press formed in a housing.

  Vibration damping devices of this type, in vehicle exhaust pipes in particular, with elastic cushions made of metallic wire formed by the press, arranged in casings, are known in the art.

  decoupling elements frame, according to the publication DE-

  A-33 21 382 or EP-A-208 128, in the form of housings containing

these elastic cushions.

  Stops, provided on the two front sides of the device

  tif, are assembled with the same junction end of the decoupling element, while a stop, assembled with the other end, engages approximately in the center of two cushions arranged one behind the other in the axial direction,

  or in a radial recess of a single cushion.

  On known devices and decoupling elements, it has basically been found that the elastic cushions only work with a very small part of their volume, namely only at the place where the forces are directly

  engaged. Most of the volume remains at rest. Other-

  I mean, the cushions have been oversized, which

  quait, in particular, the central engagement of the stop assembled with the junction end. As the housings cannot be completely closed, the cushions are also exposed to corrosive influences, namely hot exhaust gases inside the flow path, or

  impurities, humidity and salts outside this path

  roof. It has also been found that the part of the cushions, in particular, which does not work or works little

  under normal service conditions, hardens or builds up-

  te of deposits, so that the dynamic properties, available

  in new condition, change unfavorably. Given

  that prior devices of this type have achieved

  tion integrated into the decoupling elements, they must have a priori a construction specially adapted to the element

  corresponding; they cannot have a modular design

  area for different decoupling elements, and be sim-

  fully adapted during subsequent processing.

  The elastic cushions contained in the housings are difficult to handle automatically because they catch on

  easily, so that limits are set to the automa-

  tisation. Wire cushions are "fragile" products

  inherently difficult to assemble when it comes to automa-

  tion. This drawback applies all the more in the absence of a preformed (annular) cushion, but in the presence of a line

stretched.

  As a result of the oversizing, the prior damping devices and decoupling elements were also

  bulky, whether in the radial or axial direction.

  The invention therefore aims to avoid the aforementioned drawbacks.

  On a device of the type mentioned in the introduction, this objective is achieved, in accordance with the invention, by the fact that

  crankcase wall sections on the front side, external and juxta-

  placed, as stops for the elastic cushions, can move relative to each other. The housing halves and the housing wall sections, in particular, are therefore not in direct contact with each other.

  other; slots and intermediate spaces are at the

  milking provided between the housing halves and the sections of

  wall. Sections of the housing wall on the front side, external

  nes and juxtaposed, respectively arranged on one side of the elastic cushion, are therefore movable with respect to each other, in the direction of their normals also, in

particular.

  The two axial stops for the elastic cushions being placed towards the outside, that is to say in the walls of the housing for the elastic cushion, and mutually forming effective stops for damping, as well as traction movements on the two junction ends of the decoupling element, as movements pushing the latter against each other, and wall sections

  juxtaposed, in the peripheral direction in particular, to assem-

  alternately with one or the other of the junction ends of the decoupling element, therefore movable relative to each other in the axial direction, being provided on each front side of the cushion, the central stop, provided in the state of the art, could be avoided; it was thus possible to reduce the volume of the cushions, namely of the part which had been inactive until then. Compared to configurations with two cushions, arranged on either side of the central stop, it is possible to delete one, for example. The

  device according to the invention further constitutes a com-

  posing a more active dynamic. Apart from the relatively expensive cushion material gains, the configuration

  according to the invention has the advantage of being very

  pact, as to the overall length of the cutting elements

  page, in particular, in which the device is housed

  form to the invention. This advantage is essential, since no very large space is available at the mounting locations, which are particularly active for decoupling elements. Compared to the state of the art, the rate of use of the device according to the invention is higher, and the construction costs are lower. Since the elastic cushions can themselves catch on and not be separable, by means of a shaking conveyor,

  for example, limits are set on self-manufacturing

  matic decoupling elements and state of the art. On the other hand, the devices according to the invention can

  be prefabricated as simple, uncomplicated units

  (cassettes), and be transported and processed automatically

  only, as such. The cushions can be brought, in a manner known per se, in the form of a line, be cut to length directly on the housing halves, for their accommodation in the latter, and the pieces cut to length

  can be mounted automatically, so that the pro-

  no problem with the separation of the cushions.

  While a fundamental solution may be to provide

  face the wall sections, rigidly assembled

  between them and provided on the two front sides of the casing, shearing forces then being exerted and the movement being damped by shearing of the material of the

  cushions, it is provided in preferred configurations

  wall sections located opposite a wall section, movable relative to the latter, on the other front side of the casing, wall sections, rigidly assembled together, in particular , and arranged

  on both front sides of the housing, overlapping mu-

tually.

  A basic measure is to provide a single layer of cushions in the axial direction. But it can also be

  provided, in special configurations, to have more

  several layers of cushions in the axial direction, without stops

  arranged between them. Another measure may consist

  ter to juxtapose several cushions, in the peripheral direction, in particular. The device according to the invention can be produced in the form of an individual casing, to be placed on

  the periphery of the decoupling element. But it can also

  ment have an annular realization. In this case, the elastic cushions can also be annular, or be made in the form of a partial ring, by applying

  then on top of each other by their front sides ra-

  dials, or on specially provided stops; in that case

  and in the case of separate casings with elastic cushions

  ques, provided on the periphery of exhaust pipes, the cushions are arranged in radial planes, in which preferential angular movements occur between

the ends of the pipes.

  While a solution in principle consists in giving an equal dimension to the wall sections, movable one by one

  compared to the others, it can be provided, in a configuration

  preference, that the front side wall sections, movable relative to each other, have a dimension

  different, the total area of a first group of sec-

  wall sections, assembled together, being different from the total area of the group of movable wall sections

  compared to these, but also rigidly assembled

  dement between them. The group of upper total surface wall sections will then be the one which must absorb any static preloads, such as the weight of the

Exhaust system.

  Regarding the angular movements of the extremi-

  decoupling element pipe tees, provided with

  damping elements according to the invention, therefore a good possibility of angular articulation, it is provided, in a preferred configuration, that the wall sections have

  a curved, curved design in particular.

  The cushions can in principle be accommodated, without tension, in the housings of the device according to the invention. But it is provided, in a preferred configuration, that the elastic cushions are prestressed in the casings, so that, with zones of front walls deviating from each other with given movements, this does not result in any intermediate space between these and the sides

  cushions, but that the cushions follow

  wind the movement of the wall sections.

  In a preferred configuration of the device according to the invention, provision is made for the elastic cushion to be produced in the manner described below. The wire cushion formed at the press, with longitudinal edges parallel to each other, consists of a line section separated from an endless line, formed by separation of the

  endless line at a finite angle to the direction of ex-

  tension or at the longitudinal edges of this line, and folded into the desired shape, in a circle, for example. The line section can be separated from the endless line by fusion, laser cutting, high pressure cutting at

  using a liquid, or the like. In a preferred configuration

  iL is provided that the cushions, when folding the line section into a closed ring, apply flat on top of each other. The separation or cutting surfaces, applying flat one on the other, may then not be assembled, if the cushion is held in shape by the cassette and / or the peripheral casing, or be assembled together. adequately, by welding

or collage, for example.

  It can also be provided that the ends of the line section are compressed, so that they overlap when folded into an annular section, the ends, located on opposite front sides of the line section, being in particular compressed in the direction of different lateral surfaces of the latter. In these cases, the mutual assembly of the ends of the line section can be ensured by resistance welding, by sheet metal crimps adapted to the ends, by gluing,

pinning or sewing.

  In a preferred configuration, the endless line, therefore the cushion, can have an embodiment such that they consist of several juxtaposed layers, a large sleeve then being wavy at the transverse of its direction of extension and the different layers being placed on top of each other and compressed, or more sections of narrow sleeves being placed on top of each other and compressed. In an improvement, it can be provided for finished cushions, an annular cushion for example, that the layers have a concentric mutual arrangement, or that the different layers are juxtaposed in the axial direction, the different lines or layers being able to be

  kept extra by pinning.

  The invention offers for the first time a practical application for a compressed lattice or tangled line, and avoids, by the use of separate line sections directly in a simple casing

  or a cassette, subjected as such to handling

  tion, such as transport and treatment, and finally in the decoupling element, composed of the fitting and the

  bellows, as well as possibly in the elements of the

  ter covering the latter, or in the support elements extending through the bellows, the continuous and costly handling of individual cushions in metallic fabric which, as specified in the introduction, cannot be automated because they can easily be hooked and are therefore not separable in the usual way; but this possibility is offered by damping devices conforming to

  the invention, as a result of the closed casings which envelops them

  loppent. In addition, these devices can be used on

  different cutting elements and can be

  only adapted as described above, raising the preload, for different applications and different

decoupling elements.

  It is expected, in other configurations of the invention, that the elastic cushions are covered by surfaces

  of solid walls facing each other, from which extend

  tooth wall sections on the frontal side, at an angle and with a relative peripheral mutual distance, these walls engaging one another, and that end pieces

  extend at an angle to the front wall sections

  the wall sections of the housing also having

moldings.

  The cassette is simultaneously the shaping tool for the metal wire cushion, as for its folding into a ring, at least, and a definitive place for the finished product, of which

  handling is no problem.

  At the joint of the ends, in-line cushions folded into a ring have a "material defect". This defect in itself for the operation is eliminated by bridging this place by internal reinforcements and / or, as indicated in the detail above, by tightly wrapping the cushion, on all sides, by the cassette, and / or by distributing the

  service constraints on a maximum number of stops.

  Other advantages and characteristics of the invention

  emerge from the claims and the description below

  below, in which are explained examples of cons-

  truction of the invention in support of the accompanying drawings, which correspond to: Figure 1: a side view of a preferred device

  vibration damping, in accordance with the

  vention, Figure 2a: a section along line II - II of Figure 1, the cassette not yet closed, Figure 2b: a section along line II - II of Figure 1, for a closed cassette according to this figure ,

  Figure 3: a view according to Figure 1 of another configuration

  tion of the device according to the invention, Figure 4: a section along Figure 2a of another form

  of construction of the device in accordance with the invention

tion,

  Figure 5: a schematic view of the mounting of the device

  form of the invention in a decoupling element, Figure 6: another configuration of the device according to the invention, in a section similar to that of Figure 2a, Figure 7: schematic representations of embodiments of the housing elements for the shaping of the cassettes after assembly, in order to adjust a defined preload, Figure 8: an elastic cushion folded in a ring from a line section according to Figure 9, with front sides applying flat, Figure 9: the side view of a line, with cutting lines differing by an angle of 90 relative to the extension line, for the manufacture of an annular cushion according to FIG. 8,

  Figure 10: an annular cushion with compressed ends

  overlapping in the radial direction, Figure 11a: an annular cushion with overlapping press-formed ends, in frontal side view, according to the view of arrow XIa in Figure 11b, Figure 11b: a top view of the cushion of Figure 11a,

  according to arrow XIb in FIG. 11a.

  The device according to the invention for damping vibrations, in vehicle exhaust pipes, in particular, has in principle a casing 2 (FIG. 2), preferably with an annular shape, elastic cushions

  3 being arranged in this casing, namely, for a configuration

  annular ration, an annular cushion or several sector-shaped cushions, which can extend mutually by their front sides oriented in the radial direction, or which are applied on stops assembled with the casing. Several elastic cushions 3 can be

  juxtaposed in the axial direction, no rigid stop, assembled

  blocked with the casing, not being then provided between these

  deny. The casing 2, made in the form of a cassette, consists of two elements 4, 6. One of the casing elements 4 has an outer casing wall 7, from which extend wall sections 8, 9 front side, inwards, between which recesses 11, 12 are respectively formed. The wall sections 9, 8 front side, which contain the elastic cushion (s) 3, are preferably mutually offset in the peripheral direction, a recess 12 on a front side, on the wall section 8, located opposite on the other front side in an exactly symmetrical manner (Figure 3), or with a slight

  angular offset V (Figure 1). By the offset, which corresponds to

  lays a corresponding offset V 'of the wall section 9, adjacent to the recess 12, a partial overlap (corresponding to V') of the wall sections 8, 9, produced

  on opposite front sides, is obtained.

  In the unloaded state, the edges of the casing elements 4, 6

  are separated by finite distances, slits, which per-

put relative movement.

  In the symmetrical embodiment of FIG. 3, on the outer casing element 4, overlapping zones U1, U2 are obtained by the fact that the wall sections 8, 9 of the casing element 4 have a dimension greater than that

  wall sections of the inner casing member 6.

  The internal casing element 6 has a peripheral wall.

  as internal 16, from which extend outwards

  of the wall sections 17, 18 in the recesses 11, 12, formed between the wall sections 8, 9 of the external casing element 6, and which form recesses therebetween

correspondents 19, 21.

  The elastic cushion (s) 3 therefore apply on one of their front sides, viewed in the peripheral direction, alternately on wall sections 8, 17 of the casing elements 4, 6, and on the other peripheral side, seen in the same way in the peripheral direction, alternately on

  wall sections 9, 18 of the casing elements 4, 6.

  The elastic cushions 3 are prestressed in the casing 2, having been accommodated by compression in the elements of

casing 4, 6.

  The casing elements 4, 6 are respectively assembled with pipe ends of a decoupling element, connected by a flexible gas-tight pipe element, such as a bellows, or are produced on this element (see

  below for more details).

  If the ends of pipes or of junction are displaced relative to each other, this movement is transmitted to the two casing elements 4, 6. With an axial movement, according to A1, A2 in FIG. 2b, the wall sections 8, 17 are moved towards each other (while the wall sections 9, 18 move away from each other), and tend to

  subsequent compression of the elastic cushion 3, which

  in turn, due to its cushioning properties,

  ment, the movement of the wall sections 8, 9, so final-

  pipe ends (vibration damping

  tions). In the configuration of FIG. 4, the casing elements 4, 6 are made in two parts, the wall sections 8 being made in one piece with the peripheral wall 7, and the latter having an end piece 22. The sections of wall 9 are produced on an angular end piece 23, which

  can be assembled with end piece 22, for example by welding

  ple, all types of welding being possible (welding

  by Joule effect without pressure, laser welding; an assembly

  mechanical wiring, such as compression, crimping, assembly

  under pressure, is also possible).

  While the assembly of the cassette is ensured in the radial direction, in the configuration of FIGS. 1 to 2b, the external casing element 4, at least, to be produced in two parts, in the form of two semicoques, for example , an axial assembly in the direction of the axis A can be ensured

  in the configuration of figure 4.

  The elements 7, 8, 22 and 18, with the end piece 26, are first fitted, for example, so that the wall sections 18

  engage between the wall sections 8. The elastic cushion

  that 3 is then inserted from the left and pushed against the wall sections 8, 18. Then the elements 9, 23 and 16, 17, with the end piece 24, are displaced simultaneously or successively, in the axial direction also, against The left front side of the elastic cushion, the wall sections 17 engaging in the intermediate spaces between the wall sections 9, and vice versa. The desired pressure is

  exercised, then elements 22 and 23, 24 and 26 are assembled

  as described, by welding or some other technique

than known.

  Elements 22 to 26 therefore serve first of all to fix element 7, 8, 22 on element 9, 23, and / or element 16, 17, 24 on element 18, 26, to the state of prestressing of the cushion 3, but they are also used for fixing the device according to the invention, thus produced, on the connection of

  the corresponding decoupling element.

  Figure 5 is a very schematic view of an element of

  decoupling with a device according to the invention,

  vant figure 4 4. The decoupling element has pipe ends 31, 32 joined together, in a manner known per se, by a flexible pipe element

  33 gas tight, such as a metal bellows. The extreme

  pipe mite 31 is produced on an annular casing 34, covering the metal bellows 33. The end of the casing 34 is assembled firmly with the end pieces 22, 23 (by welding, for example), while it is not assembled with the casing element 6. By its end pieces 24, 26, the latter is assembled firmly (by welding, for example) with the end of the pipe 32 (at the locations marked with

crosses).

  FIG. 6 represents a configuration similar to that of FIG. 4. No section of front wall, radial, 8, 9, 17, 18, is however assembled in one piece with the peripheral walls 7, 16 of the elements of housing 4, 6,

  but these sections are made in the form of separate elements

  res with angular end caps 41, 42, 43, 44, via the

  MEDIA DESQUELS The front wall sections 8, 9, 17, 18 are assembled with the envelope wall elements

  7, 16 annular or in the form of a cylindrical envelope.

  Assembly can be carried out in a manner analogous to that

  of figure 4. In the same way, the assembly in the

  decoupling can be ensured as described in

the support of figure 5.

  FIG. 7 represents moldings 51, 52, 53, 54 on the casing elements 4, 6. By means of these moldings 51 to 54, the prestressing can be adapted later and in the desired manner, after assembly of the casing in the form of a cassette, be suitable for different applications of the prefabricated devices according to the invention, by

example.

  The configuration according to the invention of a device

  vibration damping, shaped like a pre-cassette

  previously described, offers for the first time the possibility

  tee to use in such a device a line metal wire formed in the press, known per se, as elastic cushion, in a manner practicable in terms of

  manufacturing, simple and economical in addition. It is possible

  bLe, for this purpose, to cut a section 102 of a corresponding line material 101, at a finite angle with respect to the direction of extension R of the material, and to fold it in the form of FIG. 8. With a cut perpendicular to the direction of extension, The cutting surfaces 103, 104 are not parallel, or the material of the line must be subjected to a more intense internal radial compression, than in the external radial direction. This measure being inappropriate,

  provision is made, in the preferred configuration of the

  Figures 8 and 9, that the line material is cut with surfaces 103, 104, at an angle equal to 90 relative to the direction of extension R of the material 101, namely at an angle

  such that the two cutting surfaces 103, 104 are pa-

  LINKED TOGETHER, when folding Line section 102 into a closed ring 105 (Figure 8). With such a folding, the radial internal zones are necessarily slightly pushed back, depending on the radius of the created ring 105, while the radial external zones are necessarily slightly stretched. It is not possible to indicate a precise cutting angle for this reason. The direction of cut of the surfaces 103, 104 depends on the radius or the diameter of the annular cushion to be created, but results easily from a limited number

of tests.

  Arcs B1 and B2 indicate how the lines in the

  Figure 9 are folded into an annular cushion 105.

  The cutting surfaces 103, 104 can be suitably joined together, by gluing or welding by

example.

  Figure 10 shows another preferred configuration.

  tielle, in which an overlap of the

  mites 111, 112 of a line section 102. The ends are for this purpose compressed, as shown in the figure, namely in the radial direction, so that they

overlap in the radial direction. Another solution may consist in compressing the two front sides 113,

  114 of annular section 105, so

  that this results in an overlapping region 116, perpendicular to

  area at the front sides 113, 114 (and / or parallel to their normals) in the direction of view, as shown in the figures

11a and 11b.

  In this case also, the assembly of the ends can be ensured in different ways, namely by resistance welding, gluing, pinning or sewing the overlapping ends, by means of metal wire, staples. Furthermore, the ends may be provided with crimps

  or be enshrined in them.

  The separation of the sections 102 on the cutting lines 103,

  104 of line 101 can be ensured by trimming,

  salting, fusion, laser cutting, or cutting under

  high pressure using liquid.

  Line 101 has a multilayer embodiment, preferably, a wide sleeve, compressed flat, being waved multiple times transversely in its longitudinal direction, and the waves being pressed against each other. The line can also consist of several parts, several thin sleeves being wavy, placed against each other and compressed. Where applicable, the different lines

  or layers can be assembled in addition by spin

glage.

Claims (30)

Claims.   1. Device for damping vibrations, in exhaust pipes of vehicles in particular, with an elastic cushion, at least, made of metal wire formed by the press, arranged in a casing, characterized in that wall sections of the front side casing (8, 9, 17, 18), external and juxtaposed, as stops for the elastic cushions (3), can move relative to each other other.   2. Device according to claim 1, characterized in that a wall section (8; 18) is located opposite a   wall section (17; 9), movable relative to the latter   on the other front side of the casing (2).   3. Device according to one of claims 1 and 2,   characterized in that wall sections (8, 9), assem-   rigidly locked together and arranged on both sides   front of the casing (2), overlap each other.   4. Device according to any one of the claims   previous, characterized in that wall sections, rigidly assembled together and arranged on both   front sides of the housing, are located opposite.   5. Device according to any one of the claims   previous, characterized in that a single layer of   cushions is provided in the axial direction.   6. Device according to any one of claims 1   to 4, characterized in that several layers of cushions are provided in the axial direction, without stops arranged between these last.   7. Device according to any one of the claims   previous, characterized in that several cushions are   juxtaposed, in the peripheral direction, in particular.   8. Device according to any one of claims   previous, characterized in that the front side wall sections (8, 9; 17, 18), movable relative to each other   to others, have a different dimension.   9. Device according to claim 8, characterized in that the total surface of a first group of wall sections (8, 9), assembled together, is different from the total surface of the group of wall sections (17, 18 ),   mobile in relation to the latter, but also assem- rigidly locked together.   10. Device according to any one of the claims   previous, characterized in that the wall sections (8,   9; 17, 18) have a curved embodiment.   11. Device according to claim 10, characterized in   that the wall sections (8, 9; 17, 18) have a realization domed tion.   12. Device according to any one of claims   previous, characterized in that the elastic cushions   (3) are prestressed in the housings (2).   13. Device according to any one of claims   previous, characterized in that the elastic cushions (3) are covered by facing solid wall surfaces (7, 16), from which extend front wall sections (8, 9; 17 , 18), at an angle and with a   relative peripheral mutual distance, these walls engage giant in each other.   14. Device according to any one of claims   previous, characterized in that end caps (22, 23, 24, 26, 41, 42, 43, 44) extend at an angle to the   front side wall sections (8, 9; 17, 18).   15. Device according to any one of claims   previous, characterized in that the wall sections (7, 8, 9, 16, 17, 18) of the housing (2) have moldings (51, 52, 53, 54).   16. Elastic cushions in press-formed metal wire, with longitudinal edges parallel to one another, for a   device according to any one of claims 1 to   , in particular, characterized in that the cushion (105) is formed by separation of a line section (102) from an endless line (101), at a finite angle relative to the   longitudinal edges of the line (101).   17. Cushions according to claim 16, characterized in that the line section (102) is separated by fusion of the endless line (101).   18. Cushions according to claim 16, characterized in that the line section (102) is separated from the line without fine (101) by laser cutting.   19. Cushions according to claim 16, characterized in that the line section (102) is separated from the endless line (101) by cutting under high pressure using a liquid.   20. Cushions according to any one of claims 16   19, characterized in that, when the line section (102) is folded into a closed ring, the front faces (cutting surfaces 103, 104) are laid flat on one another.   21. Cushions according to any one of claims 16   to 20, characterized in that the ends of the line section (102) are compressed so that they overlap   when folding into an annular section.   22. Cushions according to claim 21, characterized in that the ends, situated on opposite front sides of the line section (102), are compressed in the direction   different side surfaces of the latter.   23. Cushions according to any one of claims 16   to 22, characterized in that the ends of the line section (102) are mutually assembled by resistance welding.   24. Cushions according to any one of claims 16   to 22, characterized in that the ends of the line section (102) are mutually assembled by crimping of suitable sheet metal.   25. Cushions according to any one of claims 16   to 22, characterized in that the ends of the section of   line (102) are glued together.   26. Cushions according to any one of claims 16   to 22, characterized in that the ends of the section of   line (102) are pinned or sewn.   27. Cushions according to any one of claims 16   to 26, characterized in that they consist of several juxtaposed layers.   28. Cushions according to claim 27, characterized by   a mutual concentric arrangement of the layers.   29. Cushions according to claim 27, characterized in that the different layers are juxtaposed in the axial direction. 30. Device for damping vibrations according to one   any one of claims 1 to 15, characterized in that   the elastic cushions (3; 105) are made according to one   any of claims 17 to 29.